AL-Mubarak, A: Seismic Random Vibration of Joints for Above-

This study is an attempt concerning the subject of structural dynamic analysis and behavior of above-ground, cross-country pipelines subjected to earthquake ground motion. The main objective of this study is exploring the structural dynamic behavior of soft joints of straight above-ground, cross-country pipelines by adopting stochastic (non-deterministic) models of ground motion including their spatial variation using frequency domain spectral analysis The model that has been adopted in this study is multi-segmented pipelines resting on squared rigid foundation. The segments are connected by flexible joints which are modeled as springs and dashpots of hysteretic (structural) damping type in both axial and lateral normal directions, the whole system then is subjected to two perpendicular uncorrelated, non-deterministic earthquake ground motions based on different types of stochastic models which depend on the characteristics (type) of soil underneath the pipeline foundation. A special computer program has been ed and developed. The source code of the program was written using the programming language of the MATLAB computer Software.